1. Field of the Invention
The present invention relates to a fluid-driven shutoff valve including a valve seat formed in a main body, a valve element movable into or out of contact with the valve seat, a drive part integrally coupled with the valve element, and a pilot opening/closing (on/off) valve configured to supply compressed fluid to drive the drive part.
2. Related Art
As a resist supplying device of a semiconductor manufacturing apparatus, conventionally, there is used a device integrally including a suck-back valve and an air-driven shutoff valve. For a resist supplying process, there is a demand for control of an amount of resist to be supplied with high precision. For this purpose, it would be necessary to control movements of a diaphragm valve element of the air-driven shutoff valve (opening-closing control). For example, see Patent Document 1. In this case, the opening-closing control of the air-driven shutoff valve is performed by use of an electropneumatic regulator. This electropneumatic regulator generally includes an electromagnetic valve for air supply and an electromagnetic valve for air discharge and is configured to adjust secondary pressure to be constant by an electric signal in order to appropriately control primary pressure to be supplied to the electropneumatic regulator.
The electropneumatic regulator is controlled to control the movement of the diaphragm valve element to thereby reduce water hammer phenomenon which will be generated by the diaphragm valve element.